1. Field of the Invention
The present invention generally relates to a device for improved sealing of a conduit connection. More particularly, the present invention relates to a dual-plane sealing configuration for connecting a tube to a port within an automotive air-conditioning component.
2. Description of the Prior Art
Prior to the present invention, many types of sealing configurations have been proposed for connecting a tube to another component of a fluid system. Perhaps most common was the use of a simple O-ring encircling an end of a tube mounted into a port. The tube would be connected to the port using a coaxial fastener that encircled and entrapped the tube. The coaxial fastener would then be screwed down over corresponding threads on the portxe2x80x94similar to a compression fittingxe2x80x94as is known in the art. Although this configuration was very simple and robust against leakage, its primary drawback was that it could not be assembled quickly enough for the modem day assembly line. In order to torque the fastener to the female port it was necessary to use hand tools, which was too time consuming. Therefore, devices such as teardrop block connections were developed.
The teardrop block connection involves a small mounting block having a teardrop-shaped profile. The teardrop block entraps the conduit through a conduit passage therein. Also, the teardrop block houses a fastener through another passage just offset from and parallel to the conduit passage. A simple bolt-style fastener is used to draw the teardrop block and conduit to the port, where the connection can be fastened quickly with a power tool. However, the teardrop block connection tends to be more susceptible to leakage than the coaxial fastener connection.
Accordingly, there are several reasons that teardrop block connections tend to leak. First, for packaging considerations, conduit ends are typically made very short to minimize the corresponding length of the port. As a result, the short conduit end tends not to pilot within the female port as well as a longer pilot would. Second, during final torque-down the teardrop block and conduit tend to misalign, cross-axially, relative to the female port. This misalignment is often the result of the cantilever nature of the teardrop design. That is, since the longitudinal axis of the fastener is not coaxially aligned with the conduit, but is instead offset, any torquing of the fastener often imparts a cantilever effect across the teardrop block. The cantilever effect results in a maximum hold-down force along the axis of the fastener and a minimum hold-down force at the opposite end of the teardrop block at the far edge of the conduit. Therefore the mounting block often does not mount squarely to the sealing surface and likewise the conduit does not mount squarely within the port. Such cross-axial misalignment results in slight abrasion to or insufficient xe2x80x9csqueezexe2x80x9d on the O-ring, thus permitting fluid to leak by. Accordingly, such fluid leaks present a significant warranty problem to automobile manufacturers.
In response to this problem, component manufacturers have, in some applications, applied a gasket between the teardrop block and the port. FIGS. 1 and 2 illustrate a gasket 60P according to the prior art. Here, interference tabs 67P are used to help retain the gasket 60P around the conduit during shipping and assembly. However, while such a gasket may reinforce the sealing potential of the connection, the gaskets of the prior art introduce new problems. Because the gaskets are stamped from metal substrate, the interference tabs scratch and thereby create leak paths along the outer surface of the conduit as the gasket is assembled thereto. Furthermore, such gaskets incorporate no feature to counteract the inherent cantilever misalignment of typical end-form connections.
From the above, one can see that an improvement in the capability to seal a teardrop-shaped fluid connection is required. Therefore, what is needed is a sealing configuration that minimizes misalignment of the connection and incorporates additional areas of sealing within the connection.
According to the present invention there is provided a device that minimizes assembly misalignment and incorporates additional areas of sealing within the fluid-tight conduit connection. The fluid-tight conduit connection includes a conduit having a circumferential groove with a circumferential seal mounted therein. Further, an end-form block has a conduit passage through which the conduit is fitted and entrapped. Likewise, a planar seal has a formed pilot with an aperture through which the conduit is fitted. Furthermore, a receiver has a fluid passage into which the conduit is fitted, where the circumferential seal is compressed between the fluid passage and the conduit to establish a first primary seal. Similarly, the planar seal is compressed between the receiver and the end-form block to establish a second primary seal, and the formed pilot is sandwiched between the conduit and the receiver to establish a secondary seal. Finally, fastening members are included for fastening the end-form block to the receiver such that the planar seal is further compressed to complete the fluid-tight connection.
Additionally, the planar seal may include an embossment surrounding the aperture and following the periphery of the planar seal to establish a preload on the planar seal during assembly of the fluid-tight conduit connection. Similarly, the embossment may be greater in thickness near one end of the fluid-tight conduit connection than at an opposite end, so as to pre-seal one end of the fluid-tight conduit connection during assembly. Furthermore, the fastening members may include a stud and fastening nut with a conically-shaped washer overhanging the end-form block, to counterbalance alignment during assembly.
From the above, it can be seen that a significant advantage of the present invention is the introduction of an additional sealing area within the traditional conduit connection. The formed pilot of the planar seal provides the additional sealing area, thus establishing a secondary seal, in addition to the first and second primary seals.
Additionally, the conduit connection may include features that balance alignment of the end-form block and conduit to the receiver, thereby minimizing potential for leakage. The embossment of the planar seal or the conically-shaped oversize washer of the fastening members are features that counteract the inherent cantilever nature of an endform block connection.
Accordingly, it is an object of the present invention to provide an improved configuration for sealing a conduit connection.
It is another object of the present invention to provide a fluid-tight conduit connection with a planar seal that assembles smoothly over an end of a conduit without leaving scratches and leak paths on the conduit.
It is yet another object of the present invention to provide a fluid-tight conduit connection with a planar seal that yields an additional sealing area in the form of a formed pilot pinched between a receiver and an end-form block.
It is a further object of the present invention to provide a fluid-tight conduit connection with a planar seal that has a feature to help align a conduit to a port and counteract the inherent cantilever nature of an end-form block connection.
Additional objects, features, and advantages of the present invention will become apparent from a reading of the detailed description of the preferred embodiment taken in conjunction with the drawings appended hereto.